regular expressions

[oll3i]

cd anyone help me
i need to find a pattern in a file and replace it with new value
the pattern is a double

[sicarie]

cd anyone help me
i need to find a pattern in a file and replace it with new value
the pattern is a double

The word 'double' or just any double?

If it's any double and you're reading stuff in from a file, you would need to set up a Scanner, and then go line by line looking for [number].[number] .

[oll3i]

a double i need to find a double in a file and replace it with a new value
how to replace it ?

[Ganon11]

You could read the entire file into a String, find the double and replace it, and then rewrite the original file with the altered String.

[sicarie]

You could read the entire file into a String, find the double and replace it, and then rewrite the original file with the altered String.

If you read the line in (and here is where I hope that I remember correctly that were in the Java forum) you can do a Pattern.match() on a pre-compiled regex, or if you wanted to use strings, you can do String.indexOf() for the period and test both sides for numbers.

[r035198x]

a double i need to find a double in a file and replace it with a new value
how to replace it ?

Text files don't have data types. When you read from a Java program is when you choose which data type you want to read the values as. If you use scanner, you can read as double directly but since you say that you want to replace the double then you should the data as strings because Patterns are strings. Do you know the expression for a decimal number then? You might need to have a look at a regex tutorial first if you don't.

[oll3i]

why it highlights the Pattern.compile(patternStr); and
pattern.matcher(wczytane_dane); as an error
also is [0-9]{0,2}\\.{0,1}[0-9]{0,2} good for a double

 
private void write_to_file(String wplata_wyplata){
    try{
 
 
 
    BufferedReader in = new BufferedReader(new FileReader(filename));
 
 
 
    String wczytane_dane="";
    String line = in.readLine();
 
 
 
    double sd= sr_dost;
    Double a1 = new Double(sd);
 
  while((line = in.readLine()) != null)   {   
      wczytane_dane+=line;
        line = in.readLine();
 
  }
 
  String patternStr = "[0-9]{0,2}\\.{0,1}[0-9]{0,2}";
  String replacementStr = a1.toString();;
 
 
  Pattern pattern = Pattern.compile(patternStr);
 
 
  Matcher matcher = pattern.matcher(wczytane_dane);
  String output = matcher.replaceAll(replacementStr);
 
 
 
FileWriter fstream = new FileWriter("konta//"+NumerKonta+".txt");
BufferedWriter out = new BufferedWriter(fstream);
 
 
// write wczytane_dane to a file will be here
 
 
 
 
out.close();
 
 
 
 
 
    in.close();
      }catch (FileNotFoundException e) {
            System.err.println("Nie ma takiego konta(File not found!)");
      }catch (IOException e) {
              System.err.println(e);
      } catch (NumberFormatException e) {
             System.out.println("NumberFormatException: " + e.getMessage());    
      }catch (Exception ex)  {
    ex.printStackTrace();  }
 
 
}
 
 

[r035198x]

why it highlights the Pattern.compile(patternStr); and
pattern.matcher(wczytane_dane); as an error
also is [0-9]{0,2}\\.{0,1}[0-9]{0,2} good for a double

 
private void write_to_file(String wplata_wyplata){
    try{
 
 
 
    BufferedReader in = new BufferedReader(new FileReader(filename));
 
 
 
String wczytane_dane="";
String line = in.readLine();
 
 
 
double sd= sr_dost;
Double a1 = new Double(sd);
 
while((line = in.readLine()) != null) { 
     wczytane_dane+=line;
    line = in.readLine();
 
}
 
String patternStr = "[0-9]{0,2}\\.{0,1}[0-9]{0,2}";
String replacementStr = a1.toString();;
 
 
Pattern pattern = Pattern.compile(patternStr);
 
 
Matcher matcher = pattern.matcher(wczytane_dane);
String output = matcher.replaceAll(replacementStr);
 
 
 
FileWriter fstream = new FileWriter("konta//"+NumerKonta+".txt");
BufferedWriter out = new BufferedWriter(fstream);
 
 
// write wczytane_dane to a file will be here
 
 
 
 
out.close();
 
 
 
 
 
in.close();
     }catch (FileNotFoundException e) {
         System.err.println("Nie ma takiego konta(File not found!)");
     }catch (IOException e) {
     System.err.println(e);
     } catch (NumberFormatException e) {
     System.out.println("NumberFormatException: " + e.getMessage()); 
     }catch (Exception ex) {
ex.printStackTrace(); }
 
 
}
 
 

Did you import the java.util.regex package?

[oll3i]

should be

String output = matcher.replaceFirst(replacementStr); 
 

there

[oll3i]

i have imported

import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import com.sun.org.apache.xalan.internal.xsltc.compiler.P attern;

[r035198x]

should be

String output = matcher.replaceFirst(replacementStr); 
 

there

I'm sorry I don't get it. Is it a question or have you got it to work?

[oll3i]

no i havent it still highlights Pattern.compile(patternStr); (highlights the word compile)and pattern.matcher(wczytane_dane); (highlights the word matcher)as an error
i have imported
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import com.sun.org.apache.xalan.internal.xsltc.compiler.P attern;

eclipse doesnt say that i need to import some other package

[sicarie]

no i havent it still highlights Pattern.compile(patternStr); (highlights the word compile)and pattern.matcher(wczytane_dane); (highlights the word matcher)as an error
i have imported
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import com.sun.org.apache.xalan.internal.xsltc.compiler.P attern;

eclipse doesnt say that i need to import some other package

What is the error it is giving you - can you copy and paste it here?

[oll3i]

Exception in thread "AWT-EventQueue-0" java.lang.Error: Unresolved compilation problems:
The method compile(ClassGenerator, MethodGenerator) in the type Expression is not applicable for the arguments (String)
The method matcher(String) is undefined for the type Pattern

at konta_bankowe.Konto.write_to_file(Konto.java)
at konta_bankowe.Konto.depozyt(Konto.java)
at konta_bankowe.Konto.access$2(Konto.java)
at konta_bankowe.Konto$2.actionPerformed(Konto.java)
at javax.swing.AbstractButton.fireActionPerformed(Unk nown Source)
at javax.swing.AbstractButton$Handler.actionPerformed (Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed (Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent( Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(U nknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unkno wn Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(U nknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

[sicarie]

This probably won't change anything, but can you try real quick for me to change your import to import java.util.regex.*; for me?

[oll3i]

i changed the import (4u) and i still get the highlights

[r035198x]

i changed the import (4u) and i still get the highlights

Remove

 import com.sun.org.apache.xalan.internal.xsltc.compiler.P attern;
 

Just use the standard Java API with import java.util.regex.*;

[oll3i]

it fixed the prob
but it doesnt replace a double in a string is this pattern correct for a double "[0-9]{0,2}\\.{0,1}[0-9]{0,2}"; and it reads in every second line not every line i checked it with system.out

private void write_to_file(String wplata_wyplata){
    try{
 
 
 
    BufferedReader in = new BufferedReader(new FileReader("konta//"+NumerKonta+".txt"));
 
 
 
    String wczytane_dane="";
    String line = in.readLine();
 
    double sd= sr_dost;
    Double a1 = new Double(sd);
 
  while((line = in.readLine()) != null)   {   
        wczytane_dane+=line;
        line = in.readLine();
        wczytane_dane+='\n';
 
  }
 
  String patternStr = "[0-9]{0,2}\\.{0,1}[0-9]{0,2}";
  String replacementStr = a1.toString();;
 
 
  Pattern pattern = Pattern.compile(patternStr);
 
 
  Matcher matcher = pattern.matcher(wczytane_dane);
  String output = matcher.replaceFirst(replacementStr);
  System.out.println("output ze zmienionym balansem"+output); 
 
    in.close();
//here will be writing to a file
      }catch (FileNotFoundException e) {
            System.err.println("Nie ma takiego konta(File not found!)");
      }catch (IOException e) {
              System.err.println(e);
      } catch (NumberFormatException e) {
             System.out.println("NumberFormatException: " + e.getMessage());    
      }catch (Exception ex)  {
    ex.printStackTrace();  }
 
 
}
 
 

[sicarie]

it fixed the prob
but it doesnt replace a double in a string is this pattern correct for a double "[0-9]{0,2}\\.{0,1}[0-9]{0,2}"; and it reads in every second line not every line i checked it with system.out

  while((line = in.readLine()) != null)   {   
        wczytane_dane+=line;
        line = in.readLine();       
  }
 

You have two readlines - that's your 'every-other line' problem

As far as the regex goes - does the period need to be backwhacked?

I would think it would be something like [0-9]+.[0-9]+ just quick and rough, that's at least one 0-9, a period (not sure if this needs to be backwhacked or not), and at least one 0-9 digit, but could be any amount.

The way you have it, you pick up a number between 10 and 99 whose second digit is two or zero, and then three places after that. Is that what you want?

[oll3i]

thank u guys u r so helpful i dont know how i cd overlook that i had 2 readlines
... it finds and replaces the double now